JP5333779B2 - Head-up display device - Google Patents

Description

  The present invention relates to a head-up display device that visually provides various types of information such as instrument information to a driver of an automobile or the like.

  2. Description of the Related Art Conventionally, a head-up display device that projects various information images such as instrument information formed by a liquid crystal display and map information in a navigation device on a front window in a moving body such as an automobile and transmits the information to a driver is known. It has been. Patent Documents 1 and 2 disclose the use of such a head-up display device in a vehicle.

  Patent Document 1 discloses a vehicle display system that emits light including information from a light-emitting display unit toward a window glass, and causes a viewer to visually recognize the display image, and forms a light display image on the window glass. Have been described. According to this vehicle display system, since the display image visually recognized by the observer is a real image, it is possible to provide a display system that does not cause any dynamic distortion as compared with a display system using a conventional virtual image. It has become.

  Patent Document 2 discloses the use of a transparent hologram that reproduces diffused light by reflection diffraction as a combiner in a head-up display device. By using a combiner using such a hologram, it is possible to provide a combiner and a head-up display device that can observe a bright reproduced image with less blur without requiring very high flatness. It becomes possible.

  Here, an embodiment of the head-up display device will be briefly introduced with reference to FIGS. 11 and 12. FIG. 11 shows an embodiment in which various configurations of a head-up display device are incorporated in an instrument panel. Video information such as vehicle instrument information and map information from the navigation device is output and displayed on the liquid crystal display panel. A backlight as a light source is installed on the back surface of the liquid crystal display panel. By irradiating the liquid crystal display panel from the back surface, an image formed on the liquid crystal display panel is irradiated onto a concave mirror as an optical system enlarging element. The image reflected and enlarged by the concave mirror is projected on the inside of the front window or a transmissive reflector provided on the front window.

  The operator can view the display image (virtual image) located in front of the front window at the same time as the scenery outside the vehicle. In addition, by setting the distance to the display image (distance L) as far as possible, the operator can check video information such as instrument information and map information with a small amount of movement of the focal position.

  FIG. 12 is a view showing the state from behind the vehicle driver's seat, in which various types of video information are displayed within a display range surrounded by a broken line in the front window, and the driver has various types of information arranged in the instrument panel. It is possible to obtain various information by video while paying attention to driving the vehicle without dropping the line of sight to the instruments.

JP-A-8-91094 Japanese Patent Laid-Open No. 9-179058

  As disclosed in Patent Document 2, by using a hologram, a so-called holographic optical element, as a combiner, compared to the case of using a conventional half mirror or polarizing beam splitter, high see-through property that does not impair external light, It is possible to achieve both bright video display. Further, by providing the holographic optical element with a lens function (optical enlargement function), it is possible to enlarge a display image, and it is possible to simplify and downsize the system configuration.

  When a holographic optical element is used as a combiner, a holographic optical element having a large area is required to ensure a wide area image display. However, at present, it is difficult to manufacture large (large) holographic optical elements from the viewpoint of production cost and yield.

  In addition, since the holographic optical element is used by being attached (fixed) to a front window or the like, it is difficult to adjust the position, and it is difficult to adjust the position of the observer due to the difference in the physical size of the observer or the situation of the posture. It has become difficult to respond. Even in such a case, if a holographic optical element having a large area can be used, the observation position can be expanded, that is, the visible region can be expanded. However, as described above, a large holographic optical element is procured. This is a difficult situation at present.

In order to solve the above-described problem, the head-up display device of the present invention is formed to have an overlapping region in which a part of a plurality of holographic elements are bonded to each other and a region that is not bonded, and an observation position. A holographic optical system disposed opposite to the holographic optical system and a plurality of the holographic elements forming the holographic optical system.
And a projector unit that forms a virtual image that shadows and forms an image at a distance from the observation position .

  Furthermore, in the head-up display device of the present invention, the holographic element has an optical magnification function.

  Furthermore, in the head-up display device of the present invention, the holographic optical system is characterized in that the plurality of holographic optical elements are bonded in a vertical direction to an observer positioned at the observation position. Is.

  Furthermore, in the head-up display device of the present invention, the holographic optical system is characterized in that the plurality of holographic optical elements are bonded in a horizontal direction to an observer located at the observation position. Is.

Furthermore, in the head-up display device of the present invention, the holographic optical system is characterized in that the plurality of bonded holographic optical elements have different diffractivities.

According to the head-up display device of the present invention, it is possible to secure a wide area of the holographic optical system by forming the holographic optical system by bonding a part of a plurality of holographic optical elements to each other. It is possible to display an image in a wide area and to ensure a wide visible area for the observer.

The figure which shows the head-up display apparatus which concerns on embodiment of this invention. 1 is a diagram showing a projector device according to an embodiment of the present invention. The figure for demonstrating the lens function by a holographic optical system. The figure which shows the visible range of a holographic optical system. The figure which shows the mode of holographic optical system formation which concerns on embodiment of this invention. The figure which shows the visible range of the holographic optical system which concerns on embodiment of this invention. The figure for demonstrating the diffraction index of the holographic optical system which concerns on embodiment of this invention. The figure which shows the holographic optical system which concerns on other embodiment of this invention. The figure which shows the holographic optical system which concerns on other embodiment of this invention. The figure which shows the holographic optical system which concerns on other embodiment of this invention. The figure which shows the conventional head-up display apparatus. The figure which shows the mode of the image display in the vehicle interior by a head-up display apparatus.

  FIG. 1 is a diagram showing a head-up display device according to an embodiment of the present invention, and shows a case where it is adopted in an automobile. Note that the head-up display device of the present invention is not limited to an automobile, and can be employed in a display device for a driver of various vehicles, a game machine, or a simulation device.

  A front window 21 of the automobile is arranged in the observation direction of the observer, and a holographic optical system 20 is stuck inside. The holographic optical system 20 is an optical member having a see-through (transparency) property that does not impair external light and having a diffraction function, and is created by recording an interference pattern of object light and reference light. In this embodiment, it functions as a combiner that superimposes the scenery outside the passenger compartment and the video information of the projector device 10 at the observation position.

  The projector device 10 (“projector unit” in the present invention) is a device that projects an image based on various types of input video information, and can use various methods such as a liquid crystal projector, a DLP projector, and an LCOS projector. It is. The image projected from the projector device 10 is diffracted by the holographic optical system 20 and is observed as a virtual image that forms an image far away at the observer's observation position. The observer, that is, the pilot, can visually recognize the scenery outside the passenger compartment and the video information from the projector device 10 without changing the line of sight. In the present embodiment, the imaging distance can be changed by changing the focal length of the projector device 10. As a result, the imaging distance is shortened when the vehicle ahead is near, and the imaging distance is increased when there is no vehicle ahead or far away. Make it visible.

  FIG. 2 is a diagram showing a projector apparatus according to the embodiment of the present invention. In the present embodiment, a laser is used as a light source, and a liquid crystal display element is used in an image forming unit that forms an image. The laser light source 11 is a light source device including a laser semiconductor 112, a diverging optical system 111, and the like, and the output light radiated from the laser semiconductor 112 is aligned in a predetermined irradiation cross-sectional shape by the diverging optical system 111. Output to the outside.

The output light output from the laser light source 11 is adjusted to a necessary area as a backlight by the beam expander 12 and then irradiated to the back of the image forming unit 13. In the present embodiment, a liquid crystal display unit using a liquid crystal display element 131 is employed as the image forming unit 13. The output light of the laser light source 11 is adjusted by the diffusion plate 132 so that the intensity distribution is uniform, and then the image formed on the liquid crystal display element 131 is irradiated from behind and projected through the projection optical system 14. Form an image.

  An observer observes this projection image through the holographic optical system 20. This is made possible by the polarization function of the holographic optical system 20, but by providing the holographic optical system 20 with a lens function (optical magnification function), it is possible to provide a large image to the observer. In addition, the projection optical system 14 in the projector apparatus 10 can be downsized, and the projector apparatus 10 itself can be downsized.

  FIG. 3 is a diagram for explaining a holographic optical system having such a lens function. Since the holographic optical system 20 has high see-through properties, extraneous light passes through the holographic optical system 20 with almost no loss. On the other hand, incident light (reproduced light) emitted from the projection apparatus 10 is diffracted in a predetermined direction by the holographic optical system 20. By manufacturing the holographic optical system 20 so that the diffracted light is diffracted toward the condensing point, a lens function (optical magnification function) can be provided.

  FIG. 4 is a diagram for explaining the visible range of the holographic optical system. When the observer's viewpoint is within the holographic optical system 20 as shown in FIG. 4A, an image formed by the projection device 10 can be provided to the observer. However, as shown in FIG. 4 (b) and FIG. 4 (c), the observer's physique difference (in this case, the height is mainly) and the posture difference due to the seating situation on the seat, etc. When the viewpoint protrudes from the holographic optical system 20, the visible range becomes incomplete, and the image formed by the projection device 10 cannot be normally viewed. In particular, since the holographic optical system 20 is used by being fixed to the front window 21 or the like, the position adjustment cannot be performed, and thus it is difficult to adjust due to such a physique difference or a posture difference.

  FIGS. 5A and 5B are diagrams showing how the holographic optical system 20 according to the embodiment of the present invention is formed. FIG. 5A shows a front view and FIG. 5B shows a side view. Has been. In the present embodiment, a part of the two holographic optical elements 20a and 20b are bonded to each other to form the holographic optical system 20, and a wider area is secured as compared with the case where the single holographic optical element 20a and 20b are formed. It is possible. The holographic optical element used in the present embodiment plays a role as a concave mirror, that is, a lens function (optical magnification function). Any holographic optical element can be used as long as it plays such a role. May be.

  The side view of FIG. 5B shows a state where the holographic optical system 20 is affixed inside the front window 21 (vehicle compartment side). As described above, in the present embodiment, the holographic optical system 20 is attached to the inside of the front window 21, but the arrangement position is not limited to this form, and is attached to the outside of the front window 21. The front window 21 may be formed of two transparent base materials and may be sandwiched and disposed between the two transparent base materials. Further, the holographic optical system 20 may be disposed on a transparent base material provided separately from the front window 21 as well as the front window 21.

The holographic optical system 20 is formed by bonding two holographic optical elements 20a and 20b to each other so as to have an overlapping region in the height direction (Y-axis direction). In the present embodiment, the holographic optical element 20a positioned below is bonded to the holographic optical element 20b positioned above so as to overlap. The holographic optical elements 20a and 20b in the present embodiment use the same shape, size, and optical characteristics, but different elements may be used. In particular, regarding the optical characteristics, it is possible to improve the visibility in the overlapping region by changing the diffraction index.

  As described above, the two holographic optical elements 20a and 20b are bonded to each other so that an overlapping region is formed. Since each holographic optical element 20a, 20b is originally provided with optical characteristics so as to function one by one, this overlap region is different from the original optical characteristics. However, as described with reference to FIG. 1, the head-up display device of this embodiment is configured to observe an image formed at a sufficiently far distance, so that even if two optical characteristics overlap, it is visually There is little sense of incongruity.

  In order to increase the area of the holographic optical system 20, it is possible to consider arranging a plurality of holographic optical elements 20a and 20b side by side without providing an overlapping region, but the holographic optical elements 20a and 20b can be arranged without gaps. It is very difficult to dispose, and in the generated gap, even if the image is formed sufficiently far away, the visual discomfort is relatively large. In particular, when the viewpoint is moved between the holographic optical elements 20a and 20b, the sense of incongruity in the generated gap is large, and the gap, that is, the actual arrangement position of the holographic optical system 20 may be focused. . For this reason, in the present embodiment, the holographic optical system 20 is expanded by sticking the holographic optical elements 20a and 20b to each other and forming an overlapping region.

  Thus, according to the present embodiment, it is possible to provide the holographic optical system 20 having a large area while suppressing the manufacturing cost. Further, as shown in the front view of FIG. 5 (a), even when the viewpoint is moved from the point A on one holographic optical system 20a to the point B on the other holographic optical system 20b, it is smooth. It is possible to move the viewpoint.

  FIG. 6 is a view showing a visible range of the holographic optical system according to the embodiment of the present invention. As described with reference to FIG. 5, the holographic optical system 20 is formed of two holographic optical elements 20 a and 20 b, so that the area can be expanded. Further, in the present embodiment, since it is attached in the vertical direction to the observer located at the observation position, it is possible to flexibly cope with a change in the viewpoint position due to the difference in the physique or the posture of the observer. Yes. As shown in FIG. 6A to FIG. 6C, even when the holographic optical system 20 is stuck at the same position, by expanding the area, the observer's viewpoint changes. The viewpoint can be stored in the holographic optical system 20.

  FIG. 7 is a diagram for explaining the diffraction index of the holographic optical system according to the embodiment of the present invention. This figure is an enlarged view of the overlapping region in the side view of FIG. Incident light emitted from the projector device 10 incident from the left side in the figure generates diffracted light a by the first holographic optical element 20a. On the other hand, the transmitted light a that has passed through the first holographic optical element 20a generates diffracted light b at the second holographic optical element 20b and transmits the transmitted light b. In the drawing, the holographic optical elements 20a and 20b have the same optical characteristics, and the diffracted light a and the diffracted light b are viewed by the pilot as parallel light. Should be visually recognized. However, since the holographic optical element is actually very thin, the difference between the diffracted light a and the diffracted light b is very small and can be visually recognized by the operator without any problem.

  In the present embodiment, the same optical characteristics are used as the two holographic optical elements 20a and 20b. Preferably, however, the holographic optical elements 20a and 20b have different diffractive indexes in the overlapping relationship of the overlapping regions. Good. Specifically, the diffractive index of one holographic optical element 20a (holographic with respect to incident light) that is located on the incident light side (left side in the figure, the front surface with respect to the incident light) and that constitutes the holographic optical system. The power ratio of the diffracted light a of the optical element 20a is positioned on the transmitted light side of the incident light from the holographic optical element 20a (the right side in the figure, the position on the front side with respect to the transmitted light a), and the holographic optical system By making the refractive index lower than the diffractive index of the other holographic optical element 20b constituting the power (the power ratio of the diffracted light b of the holographic optical element 20b to the transmitted light a), an image with less discomfort can be provided in the overlapping region. It becomes possible to do. Further, as viewed from the observer, the power ratio of the diffracted light a and the diffracted light b is designed to be equal, so that not only the overlapping region of the holographic optical element 20a and the holographic optical element 20b but also the holographic optical system. Even in the whole 20, it is possible to provide an image with less discomfort.

  The difference in diffraction index between the plurality of holographic optical elements 20a and 20b may be different in each of the holographic optical elements 20a and 20b, or may be different only in the overlapping region. If only the overlapping regions can be made different, it is possible to suppress a sense of incongruity in the entire holographic optical system 20 by aligning the diffractive index in the portion where each holographic optical element 20a, 20b exists independently. On the other hand, if the holographic optical elements 20a and 20b have different diffractive indexes, there is no need to change the diffractive index in one holographic optical element 20a and 20, so that a general-purpose holographic optical element is used. It can be used and the manufacturing cost can be reduced.

  In the present embodiment, the case where two holographic optical elements 20a and 20b are overlapped has been described. However, even when three or more holographic optical elements are overlapped, the diffraction rate increases from the observation position toward the imaging side. By doing so, it is possible to reduce the uncomfortable feeling of the image formed in the overlapping region.

  As described above, the holographic optical system according to the embodiment of the present invention has been described with reference to FIGS. 5 to 7. However, according to the present invention, the holographic optical system according to the embodiment of the present invention can be reduced with a simple configuration while suppressing the uncomfortable feeling of the observed elephant. It is possible to expand the area of the graphic optical system. In particular, in the present embodiment, it is possible to flexibly deal with the difference in the physique and the posture of the observer by attaching the observer positioned at the observation position in the vertical direction.

  8 to 10 are diagrams showing a holographic optical system according to another embodiment of the present invention. In the embodiment described with reference to FIG. 5, two holographic optical elements are bonded in the vertical direction. However, the present invention is not limited to this form, and other forms can be adopted.

  FIG. 8 shows an embodiment in which three holographic optical elements 20a to 20c are bonded in the vertical direction as in FIG. 5. According to such an embodiment, the holographic optical system 20 can be further expanded. It becomes possible to plan.

  FIG. 9 shows an embodiment in which two holographic optical elements 20a and 20b are bonded in the horizontal direction (X direction in FIG. 5) to an observer located at the observation position. According to such an embodiment, the visible range can be visually recognized even when the observer moves in the horizontal direction. Further, it is possible to enlarge the image in the horizontal direction of the observer, and it is possible to provide more information to the observer. Further, by arranging more holographic optical elements in the same manner, it becomes possible to make the display visible to a plurality of observers.

  FIG. 10 shows an embodiment in which four holographic optical elements 20a to 20d are bonded together. According to such an embodiment, it is possible to expand the observation area in both the vertical and horizontal directions of the observer, and it is possible to flexibly deal with the difference in the physique and posture of the observer And more information can be provided to the observer.

  As mentioned above, although other embodiment of the holographic optical system 20 was described using FIGS. 8-10, not only these embodiments but the holographic optical elements 20a-20d employ | adopt a duplication form suitably. Is possible. Also, different shapes and optical characteristics of the holographic optical elements 20a to 20d may be used.

  Note that the present invention is not limited to these embodiments, and embodiments configured by appropriately combining the configurations of the respective embodiments also fall within the scope of the present invention.

DESCRIPTION OF SYMBOLS 10 ... Projector apparatus, 11 ... Laser light source, 111 ... Divergence optical system, 112 ... Laser semiconductor, 12 ... Beam expander, 13 ... Image forming part, 131 ... Liquid crystal display element, 132 ... Diffusing plate, 14 ... Projection optical system, 20 ... Holographic optical system, 20a to 20d ... Holographic optical element, 21 ... Front window

Claims (4)

A holographic optical system that is formed to have an overlapping region in which a part of a plurality of holographic elements are bonded to each other and a region that is not bonded, and that is disposed to face an observation position;
A projector unit that projects a video onto the plurality of holographic elements forming the holographic optical system and forms a virtual image that forms a distant image at the observation position. Display device. The head-up display device according to claim 1, wherein the holographic element has an optical magnification function. 3. The head according to claim 1, wherein the holographic optical system is configured such that the plurality of holographic optical elements are bonded in a vertical direction to an observer located at the observation position. Up display device. The holographic optical system is characterized in that the plurality of holographic optical elements are bonded in a horizontal direction to an observer located at the observation position. The head-up display device according to Item.

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